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AGRICULTURAL SCIENCES – Vol. II - Fertilizer Use in Sub-Saharan Africa: Types and Amounts - V.A. Kelly and A. Naseem
FERTILIZER USE IN SUB-SAHARAN AFRICA: TYPES AND
AMOUNTS
V.A. Kelly and A. Naseem
Department of Agricultural Economics, Michigan State University, USA
Keywords: Fertilizer, Sub-Saharan Africa, soil degradation,
Contents
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1. History of Fertilizer Use in Sub-Sahara Africa
1.1. Background
1.2 Quantities of Fertilizer Consumed
1.3. Intensity of Fertilizer Use
1.4. Types of Fertilizers Used
2. Factors Influencing the Growth of Fertilizer Use
2.1 Historical and Policy Influences
2.2. Agro-ecological Zones and Other Geographic Factors
2.3. Colonial Heritage
2.4. Demography
2.5. National Income
2.6. Infrastructure
2.7. Crop Choice
2.8 Prices and Profitability
3. The Effect of Fertilizer Use on Crop Production and the Environment
4. Future Trends Anticipated
Acknowledgements
Glossary
Bibliography
Biographical Sketches
Summary
The salient characteristics of fertilizer use in Sub-Saharan Africa (SSA) are (1) the
extremely small quantities of both organic and inorganic fertilizers used, (2) the very low
intensity (kg/ha) of use, and (3) the slow rates of growth in fertilizer consumption.
While many parts of the world are correctly concerned about the negative environmental
impacts of excessive fertilizer use (eutrophication, salinization, aluminum toxicity, etc.),
most of SSA is suffering the negative environmental consequences of too little fertilizer use
(rapid loss of soil nutrients, inadequate production of biomass for recycling nutrients and
soil organic matter, loss of forests and woodlands due to continuation of shifting
cultivation, expansion of cultivation to marginal lands with a high propensity for erosion,
etc.).
Aggregate fertilizer consumption in SSA will probably continue to grow slowly during the
next five to ten years with inter-annual fluctuations in consumption remaining important in
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AGRICULTURAL SCIENCES – Vol. II - Fertilizer Use in Sub-Saharan Africa: Types and Amounts - V.A. Kelly and A. Naseem
many countries as they continue to struggle with economic reforms and programs to
liberalization both input and output markets. Nevertheless, there is some evidence from
individual country studies that both fertilizer demand and supply are becoming more
dependable for specific cropping systems.
1. History of Fertilizer Use in Sub-Saharan Africa
The salient characteristics of fertilizer use in Sub-Saharan Africa (SSA) are (1) extremely
small quantities of both organic and inorganic fertilizers used, (2) very low intensity
(kg/ha) of use, and (3) slow rates of growth in fertilizer consumption.
1.1. Background
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Historically, African agriculture has been characterized as a land-abundant production
system. Under these conditions, farmers cultivated the same land for several years. Crop
residues and animal manure were used by some to maintain soil quality, but most farmers
relied on shifting cultivation rather than soil amendments to maintain yields. When yields
declined, farmers cleared new land, allowing the previously cultivated land to lie fallow for
ten to fifteen years.
During this fallow period, soil nutrients and soil organic matter were rebuilt. If the fallow
period was extremely long, soil quality might have approached its pre-disturbance level,
but this would have been an extremely rare situation. The more common case was a shorter
fallow period followed by another cycle of cultivation without application of fertilizers—all
of this leading to a secular decline in soil quality.
During the last few decades, SSA has experienced some of the highest population growth
rates in the world (3 to 4% per annum). Rapid population growth has placed heavy
demands on arable land in SSA where 50 to 90% of the population (depending on the
country) rely on agriculture for their livelihood.
Consequently, many parts of SSA are now considered land-constrained because population
densities are too great for farmers to allow their land to lie fallow for 10-15 years.
Although information on fallows is not abundant, scattered evidence suggests that current
fallows rarely exceed 2 to 3 years—a period that is much too short to rebuild soil quality.
Unfortunately, the decline in fallows has not been accompanied by the necessary increase
in use of fertilizers (both organic and inorganic) to maintain soil quality and yields.
1.2 Quantities of Fertilizer Consumed
Overall, the entire African continent (including North African countries and South Africa)
accounts for only 2 to 3% of world fertilizer consumption; the share for SSA is generally
less than 1%. Figure 1 shows trends in aggregate fertilizer use for each of the five agroecological regions of SSA from 1961 through 1998 (for a break-down of the Regions, see
the Glossary).
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AGRICULTURAL SCIENCES – Vol. II - Fertilizer Use in Sub-Saharan Africa: Types and Amounts - V.A. Kelly and A. Naseem
Figure 1. SSA fertilizer consumption: 1961-1998
During these four decades the Central African Region and the Sudano-Sahelian countries
have generally consumed less fertilizer than other regions while the Southern and Eastern
African regions consumed more.
Although Coastal West Africa had very low consumption during the 1960s, there was
strong growth during the 1970s and by the late 1980s it was consuming more than either
East or Southern Africa.
All regions except Central Africa experienced some sustained growth in fertilizer
consumption between the late 1970s and the early 1990s. However, average SSA growth
rates (about 7%) remain well below those in other regions of the world with rapid growth in
agricultural productivity (e.g. 11% for Asia and 22% for south-east Asia from 1970-1995).
These regional figures mask a great deal of variability among SSA countries. For example,
from 1991 to 1995 four countries (Ethiopia, Kenya, Nigeria, and Zimbabwe) accounted for
60% of all SSA fertilizer consumption. On a regional basis, Cameroon accounted for 69%
of Central Africa=s 1991-1995 consumption, and Nigeria for 82% of the Coastal West
African consumption.
1.3. Intensity of Fertilizer Use
Figure 2 examines the intensity of fertilizer consumption by region for the last three
decades. Intensity of use is represented by estimates of kilograms of fertilizer used per
hectare of arable land (including land in permanent crops).
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AGRICULTURAL SCIENCES – Vol. II - Fertilizer Use in Sub-Saharan Africa: Types and Amounts - V.A. Kelly and A. Naseem
Figure 2. SSA intensity of fertilizer use: 1961-1998
Southern Africa (ranging from 10 to 20 kg/ha, depending on the year) is well ahead of the
other regions; but the gap has been closing, with East Africa a close runner-up since the
beginning of the 1990s (range of 10-15 kg/ha).
The Central African region and the Sudano-Sahelian countries remained below 5 kg/ha du
ring most of the period while Coastal West Africa has been in the 5-12 kg/ha range since
the early 1980s. Some of these regional averages are heavily influenced by individual
country observations.
For example during the 1991-1995 period, the sugar-producing Mauritus had an
extraordinarily high rate (by SSA standards) of 259 kg/ha while Uganda had a very low rate
of 0.20 kg/ha.
Overall, the average intensity of fertilizer use throughout SSA (increasing from 3 kg/ha in
1970 to 10 kg/ha in 1995 and then declining to 9 kg/ha in 1997) remains much lower than
elsewhere (e.g. 54 kg/ha in Latin America, 80 kg/ha in South Asia, and 87 kg/ha in
Southeast Asia).
1.4. Types of Fertilizers Used
The nutrient content of fertilizers consumed in SSA has remained relatively constant over
time (Figure 3). Nitrogen represents the most important nutrient, accounting for about 52%
of consumption from year to year. Phosphorus has increased slightly from about 26% to
about 30%, and potassium has declined from about 22% to 18%.
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AGRICULTURAL SCIENCES – Vol. II - Fertilizer Use in Sub-Saharan Africa: Types and Amounts - V.A. Kelly and A. Naseem
Figure 3. SSA fertilizer consumption trends by nutrient
Data available on different types of fertilizers consumed (e.g., DAP, MAP, urea, NPK
complexes, etc.) are very patchy across countries making it difficult to say with certainty if
changes have occurred in the types of fertilizers used.
In many SSA countries, fertilizer supplies are often provided as in-kind aid by bilateral
donors (e.g. Japan or European countries) who tend to send NPK complexes. Since the
1980s, however, some countries have begun importing higher analysis fertilizers such as
DAP and urea.
Figure 4 shows that urea consumed in 1995 was six times greater than that consumed in
1970.
As total nitrogen consumption in the 1990s was only two times what it was in the 1970s
(Figure 3), this six-fold increase in urea probably represents a switch from reliance on NPK
complexes and lower-analysis nitrogen fertilizers.
Figure 4 also shows that the relative importance of countries consuming urea has changed
dramatically with time. In 1970, Sudan accounted for almost 90% of SSA=s urea
consumption, but in 1995 it represented about 15%, with approximately 40% being
consumed by Côte d=Ivoire, Nigeria, and Zambia and the remaining 45% being distributed
across a broad spectrum of other SSA countries.
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AGRICULTURAL SCIENCES – Vol. II - Fertilizer Use in Sub-Saharan Africa: Types and Amounts - V.A. Kelly and A. Naseem
Figure 4. Evolution of SSA urea consumption
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Bibliography
Bumb, B. and C. Baanante. (1996). The Role of Fertilizer in Sustaining Food Security and Protecting the
©Encyclopedia of Life Support Systems (EOLSS)
AGRICULTURAL SCIENCES – Vol. II - Fertilizer Use in Sub-Saharan Africa: Types and Amounts - V.A. Kelly and A. Naseem
Environment to 2020. Food, Agriculture, and the Environment Discussion Paper 17. International Food Policy
Research Institution, Washington, DC. [Overview of problems and prospects for increasing fertilizer use in
SSA with a focus on policy issues.]
Buresh, R., P. Sanchez, and F. Calhoun (1997). Replenishing Soil Fertility in Africa. Special Publication
Number 51, Soil Science Society of America and American Society of Agronomy, Madison, WI. [Proceedings
of an international symposium held in 1996; document provides extensive review of current state of
knowledge about replenishing soil fertility in SSA and contains many additional references to scientific works
dealing with the topic.]
Naseem, A. and V. Kelly (1999). Macro Trends and Determinants of Fertilizer Use in Sub-Saharan Africa.
Michigan State University International Development Working Paper No. 73, E. Lansing, MI. [Presents
detailed discussion of determinants of fertilizer consumption in SSA, showing changes in relative importance
of some determinants over time.]
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Weight, D. and V. Kelly (1999). Fertilizer Impacts on Soils and Crops of Sub-Saharan Africa. Michigan State
University International Development Paper No. 21, E. Lansing, MI. [Detailed discussion of the positive and
negative impacts that fertilizers can have in SSA and argues for a soil fertility approach that combines organic
and inorganic fertilizers with appropriate management practices.]
Yanggen, D., V. Kelly, R. Reardon, and A. Naseem (1998). Incentives for Fertilizer Use in Sub-Saharan
Africa: A Review of Empirical Evidence on Fertilizer Yield Response and Profitability. Michigan State
University International Development Working Paper No. 70, E. Lansing, MI. [Presents a detailed review of
SSA fertilizer response data with comparisons to other parts of the world and synthesizes evidence of fertilizer
profitability in SSA.]
Biographical Sketches
Valerie Kelly is Associate Professor for International Development in the Department of Agricultural
Economics at Michigan State University. Her research has focused on agricultural productivity issues in subSaharan Africa, particularly the development of policies that promote adoption of improved soil fertility
management practices. She is editing a 2003 issue of the journal Food Policy on input use and market
development in sub-Saharan Africa and has contributed to several MSU International Development Papers
dealing with soil issues available at http://www.aec.msu.edu/ agecon/fs2/. She has also published several book
chapters and journal articles dealing with input use and soil fertility issues in Rwanda, Mali, and Senegal.
Anwar Naseem is a Research Associate in the Department of Agricultural, Food, and Resource Economics at
Rutgers University. His current research interest is focused on understanding the generation, transfer and
impacts of innovation in agricultural biotechnology. He is especially interested in how public and private
research sectors interact and affect innovative activity, industry structure, patent rights, and access to
technological inputs in biotechnology. He also maintains an active interest in production and environmental
economic issues in developing country settings, particularly those relating to estimating the distribution of
benefits (both environmental and economic) from the adoption of new technologies. He received a Ph.D. in
agricultural economics from Michigan State University and a M.S. from the University of Pennsylvania.
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